At What Point Does 'Based on a Historical Character' Become Unhistorical?

[mlinssen]

ΙΣ ever being used for the word 'man'?

Twice in Eusebius. Implicitly in Justin. Your Ben says so and Irenaeus too.

Produce the manuscript then

[Secret Alias]

Philo (implicit in statements about Israel and "prevailing" word play from Gen 32:29)
Justin Second Apology and statement about Israel being "man overcoming God")
Every Church Father who used the "man seeing God" explanation for Israel which is pretty much all the Fathers
Origen Commentary on Matthew
Origen Letter to Africanus
Eusebius Preparation for the Gospel (best/least mistake prone surviving manuscript family but not the oldest)
Jerome Commentary
Diodorus of Tarsus (reference in some other Father)

No question about this.

[Secret Alias]

Another witness according to Cantor:

By itself, it is transcribed as ις (Ps. 92:4). After the definite article, it is transcribed as ἀῒς with trema on ι (Ps. 1:1). A variant in the Vatican MS has αεις (Ps. 1:1). Like ραϊθ/ραειθ*, the variant spellings ἀῒς/αεις support the idea that αϊ was a transcription convention equivalent to αει